The role of composition in the structure and water-binding in alkali-silica reaction sol and gel

Mehdi Rashidi, Alvaro Paul, Changwoo Do, Kimberly E. Kurtis

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The discrepancy between alkali cation (Na+) used in accelerated assessments of potential alkali-silica reactivity (ASR) and those predominant in portland cements (larger amounts of K+ than Na+) leads to questions regarding the reliability of standardized test methods to predict concrete field performance. To better understand the role of alkali cation type in ASR, this study investigates the influence of alkali cation type on the structure and water-binding ability of ASR sols and gels of varying composition. Results obtained by small-angle neutron scattering, 1H NMR relaxometry, and rheological measurements indicate the formation of densified agglomerate structures with increasing silica-to-alkali molar mass ratios (S/A). However, Na-based sols exhibit a greater tendency to agglomerate and a higher dynamic viscosity than K-based ones. Furthermore, at high S/A, 1H NMR relaxometry shows the greater ability of K-based gels to bind water, suggesting the better dispersion of siliceous structures and the development of finer porosities.

Original languageEnglish
Article number105814
JournalCement and Concrete Research
Volume124
DOIs
StatePublished - Oct 2019

Bibliographical note

Funding Information:
This material is based upon work supported by the National Science Foundation (NSF) under Grant No. CMMI-1234035 . Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. In addition, authors would like to thank Dr. Christopher R. Shearer for his help in preparing samples mix design and data collection, Mr. Marc CL Knapp for sample preparation and data collection, and ORNL staff for accommodation during SANS measurements. Dr. Johannes Leisen's suggestions and instructions for performing 1 H NMR are highly appreciated. Finally, we would like to thank Dr. Chetali Gupta for measuring the dynamic viscosity of sols.

Funding Information:
This material is based upon work supported by the National Science Foundation (NSF) under Grant No. CMMI-1234035. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. In addition, authors would like to thank Dr. Christopher R. Shearer for his help in preparing samples mix design and data collection, Mr. Marc CL Knapp for sample preparation and data collection, and ORNL staff for accommodation during SANS measurements. Dr. Johannes Leisen's suggestions and instructions for performing 1H NMR are highly appreciated. Finally, we would like to thank Dr. Chetali Gupta for measuring the dynamic viscosity of sols.

Publisher Copyright:
© 2019 Elsevier Ltd

Keywords

  • Alkali-aggregate reaction (C)
  • Amorphous material (B)
  • Characterization (B)
  • Rheology (A)
  • Small-angle neutron scattering

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